Hanuman was born to 'Anjana', a female vanara in present day Aanjan village in Gumla, Jharkhand. Anjana was actually an apsara or a celestial being, named 'Punjikasthala', who, due to a curse, was born on the earth as a female vanara. The curse was to be removed upon her giving birth to an incarnation of Lord Shiva. It is also said that Hanuman was born on Anjaneya Hill, in Hampi, Karnataka, near the Risyamukha mountain on the banks of the Pampa, where Sugreeva and Sri Rama met. There is a temple that marks the spot.
Along with Kesari, Anjana performed intense prayers to Shiva to beget Him as her Child. Pleased with their devotion, Shiva granted them the boon they sought. The Valmiki Ramayana, Yuddha Kanda states that Kesari is the son of Brihaspati and that Kesari also fought on Rama's side in the war against Ravana.
Different stories are told as to Hanuman's birth. One is that at the time that Anjana was worshipping Lord Shiva, elsewhere, Dashrath, the king of Ayodhya, was performing the Putrakama Yagna in order to have children. As a result, he received some sacred pudding, to be shared by his three wives, leading to the births of Lord Rama, Lakshmana, Bharata and Shatrughna. By divine ordinance, a kite snatched a fragment of that pudding, and dropped it while flying over the forest where Anjana was engaged in worship. Vayu, the Hindu deity of the wind, delivered the falling pudding to the outstretched hands of Anjana, who consumed it. Hanuman was born to her as a result.
Being Anjana's son, Hanuman is also called Anjaneya (pronounced Aanjanèya), which literally means "arising from Anjani".
Sri Aurobindo states that "vanara" does not refer to "monkey": "Prajapati manifests as Vishnu Upendra incarnate in the animal or Pashu in whom the four Manus have already manifested themselves, and the first human creature who appears is, in this Kalpa, the Vanara, not the animal Ape, but man with the Ape nature", i.e. primitive man such as Homo erectus.
Hanuman, in one interpretation, is also considered as the incarnation of Shiva or reflection of Shiva. Others, such as followers of Dvaita consider Hanuman to be the son of Vayu or a manifestation of Vayu, the god of wind. When Ravana tried to enter the Himalayas (the abode of Shiva) Nandi stopped him and Ravana called Nandi a monkey. Nandi in return cursed Ravana: monkeys would help destroy him. In the process word monkey along with panchaksram "Om Namashivaya" hit Shiva. Shiva, to give respect to his devotee, took the form of a vanara, Hanuman.